This should be our principal effort, then; this should be constantly pursued as the fixed goal of our heart, so that our mind may always be attached to divine things and to God. Whatever is different from this, however great it may be, is nevertheless to be judged as secondary or even as base, and indeed as harmful.
Martha and Mary are very beautifully portrayed in the Gospel as examples of this attitude and manner of behavior. For although Martha was indeed devoting herself to a holy service, ministering as she was to the Lord himself and to his disciples, while Mary was intent only on spiritual teaching and was clinging to Jesus’ feet, which she was kissing and anointing with the ointment of a good confession, yet it was she whom the Lord preferred, because she chose the better part, and one which could not be taken from her. For as Martha was toiling with devout concern and was distracted with her work, she saw that she could not accomplish so large a task by herself, and she asked the Lord for her sister’s help: “Does it not concern You that my sister has left me to serve by myself? Tell her to help me, then.” She was calling her not to a disreputable task, to be sure, but to a praiseworthy service. Yet what did she hear from the Lord? “Martha, Martha, you are concerned and troubled about many things, but few things are necessary, or even one. Mary has chosen the good part, which shall not be taken away from her.”
You see, then, that the Lord considered the chief good to reside in theoria alone—that is, in divine contemplation. Hence we take the view that the other virtues, although we consider them necessary and useful and good, are to be accounted secondary because they are all practiced for the purpose of obtaining this one thing. For when the Lord said: “You are concerned and troubled about many things, but few things are necessary, or even one,” he placed the highest good not in carrying out some work, however praiseworthy, but in the truly simple and unified contemplation of Him, declaring that “few things” are necessary for perfect blessedness—namely, that theoria which is first established by reflecting on a few holy persons. Ascending from the contemplation of these persons, someone who is still advancing will arrive with his help at that which is also called “one”—namely, the vision of God alone, so that, when he has gone beyond even the acts of holy persons and their wonderful works, he may be fed on the beauty and knowledge of God alone. So it is that “Mary has chosen the good part, which shall not be taken from her.” This too should be looked at more closely. For when He says: “Mary has chosen the good part,” although He says nothing about Martha and certainly does not seem to reprimand her, nonetheless in praising the former He asserts that the latter occupies a lower position. Again, when He says: “Which shall not be taken from her,” He indicates that the latter’s position could be taken from her (for a person cannot uninterruptedly practice a ministry in the body), but He teaches that the zeal of the former can surely not come to an end in any age.
John Cassian, The Conferences 1.8